The present invention relates to a signal compression recording and reproducing method, and more particularly to such a method for cases wherein signals of similar amplitude ranges occur continuously.
Signal recording methods include analog recording as well as recording digitally. However, the latter requires sampling and quantizing operations: the sampling is to record the signal at predetermined time-axis intervals, and the quantizing is to divide amplitude-axis into the amplitude-sections and then to record a representative value of the amplitude-section.
Conventionally, an original signal is converted into digital data via an A/D converter, that is, its amplitude over a predetermined interval is converted into binary data through sampling and quantizing. Then, the digitized data is compressed using various data-compressing algorithms. The digital data compressed using the above process is recorded on a recording medium as a signal having a physical quantity corresponding to the data. At this time, the recorded signal quantity is divided into just two values, unlike an analog signal quantity.
A conventional reproducing method corresponding to the above conventional compression recording method is as follows.
After a recorded signal is read out to be converted into digital data corresponding to a playback signal, the digital data is converted back into original digital data using a data-expanding algorithm which corresponds to the algorithm used for compression. The signal is converted to the original signal via a D/A converter. That is, a signal is converted into digital data and then is compressed and expanded, so that high speed operation is required and the circuit design becomes complicated for real-time processing, thereby increasing the cost.